The present invention relates to a copier, laser printer, facsimile apparatus or similar electrophotographic image forming apparatus and, more particularly, to a device for supporting an image carrier included in such an apparatus and implemented as a photoconductive drum.
It has been customary with an image forming apparatus of the type described to rotatably mount an image carrier, e.g., a photoconductive drum on a shaft which is affixed to the side walls of the apparatus body. To replace the drum, the shaft is unlocked and then removed from the apparatus body and drum so as to release the drum. Subsequently, the drum is removed from the apparatus body. The drum may be constructed into a unit together with a section for storing fresh toner and a section for collecting used toner or waste toner, as known in the art. This kind of unit is also removed from the apparatus body by pulling out a shaft supporting the drum and then removing the entire unit from the apparatus body. In any case, the drum is replaced after the shaft supporting it has been pulled out. However, pulling out the shaft from the apparatus body and drum with one hand while holding the drum with the other hand is not only time- and labor-consuming but also needs a great deal of skill. Moreover, despite that a new drum to be mounted to the apparatus body should have the photoconductive surface thereof kept off the operator's hands, the portion of the drum which can be directly touched is limted. In this way, the operation for mounting and dismounting a photoconductive drum available with the conventional apparatus is troublesome.
Further, in the unit configuration mentioned above, the shaft of the drum is supported by the apparatus body while a developing roller is supported by the unit. This brings about a problem that the distance between the drum and the developing roller is fixed. When the drum and developing roller fail to contact each other evenly in the axial direction or are not parallel to each other due to, e.g., irregularities in their outside diameters, the resulting images suffer from irregularities.